chapter 4-tissues Flashcards
histology
study of cells
mesoderm
the primary germ layer that will give rise to all the muscle tissue and all the connective tissue of the body
what surface area expansion specialization would be expected on the apical surface of an epithelium involved in absorption, such as the simple columnar epithelium of the intestine?
mircovili
gap junction
the specific adhesion composed of connexons that allows for communication
the type of epithelial tissue that makes up the pancreas, the salivary glands & the thyroid, it’s single layer of cells that are as tall as they are wide
simple cuboidal epithelium
transitional epithelium
type epithelium that is designed to stretch and changes shape when it does so
pseudostratified columnar epithelium
consists of both short cells & tall cells with cilia on the apical surface, it lines the respiratory tract
apocrine secretion
type of exocrine secretion where the whole apical region of the cell is shed to release the secretion
serous glands
producing a secretion of watery enzymes
the matrix of connective tissue is composed of fibers and what else?
ground substance
mesenchyme
all connective tissue types are derived from the embryonic version of connective tissue
reticular fibers (collagen protein)
connective tissue fibers that are composed of collagen protein that is arranged in a branchy framework to support cells
fibroblasts
-the most common cell type in connective tissue
-they are responsible for producing the matrix
mast cells
connective tissue cells that release histamine & heparin to induce inflammation in response to injury
what is the type of connective tissue located just under the basal lamina beneath an epithelium?
areolar
what is the function of an adipocyte in an adult?
store triglycerides (fat)
what connective tissue consists of a mesh of collagen fibers running in many different directions?
dense irregular
when the matrix contains chondroitin sulfate, the connective tissue is a type of what?
cartilage
chondrocytes are located in spaces called what?
lacunae
what type of cartilage contains very fine fibers in a waxy or glassy matrix and makes up articular surfaces?
hyaline
bone matrix is specialized for strength with what salts?
calcium
connective tissue layer of a mucous membrane is called the what?
lamina propia
what membranes are composed of areolar connective tissue only with no epithelium?
synovial
skeletal muscle appears striated due to the myofibril organization of the contractile proteins what? and myosin
actin
axon
part of a neuron that send messages to the next cell
A visible scar of collagen following an injury is called a what?
fibrosis
repeated damage or inflammation can lead to what, the initial change in the normal size, shape, or organization of cells?
dysplasia (reversible)
what are the two versions of general adhesion(“glue”)
cell adhesion molecules (CAMs) & intercellular cement
cell adhesion molecules (CAMs)
-connect adjacent membranes or bind extracellular materials (basal lamina)
-“big glue”
intercellular cement
-thin layer of hyaluronan (proteoglycan: protein + carbohydrate) that attaches adjacent membranes
-“small glue”
specific adhension
-cell junction
-uses large molecules
what are the types of specific adhesion?
tight junctions, gap junctions & desmosomes
tight junctions
interlocking proteins, binds lipid portion of membrane, water tight seal
desmosomes
CAMs + intercellular cement on dense are attached to cytoskeleton, resist stretching and twisting
what are the three types of desmosomes?
belt desmosomes, button desmosomes & hemidesmosomes
belt desmosomes
continuous band in apical region attached to microfilaments
button desmosomes
“spot welds” attached to the intermediate filaments
hemidesmosomes
half button desmosome at basal surface that attaches to basal lamina
inflammation events 1-2
- tissue damaged by an external factor, damaged cells release prostaglandins & undergo necrosis that triggers inflammatory response
- mast cells release histamine in response to changes in local environment and trigger vasodilation
vasodilation
smooth muscle cells in local blood vessels dilate resulting in an acceleration of blood flow to the area
inflammation events 3-4
- endothelial cells of blood cells of the blood vessels become leaky & plasma enters the wound delivering leukocytes & clotting proteins to the wound
- a clot forms around the injury isolating the site, phagocytic leukocytes (neutrophils & macrophages) engulfed pathogens and cell debris
inflammation events 5-6
- fibroblasts migrate to the wound and are stimulated to secrete collagen to form a fiber scar to reinforce the clot and begin repair
- the damaged tissue is repaired/replaced depending on the injury & type of tissue
regeneration
replacement of collagen with original tissue type, the repair will not be visible
fibrosis
visible scar of collagen, tissue is completely replaced by a dense collagen patch, tissue type function is lost at the site of the scar
tissues
collection of specialized cells that perform specific function
histology
study of cells
4 major tissue types
- epithelium “covering”-surfaces, linings, glands
- connective “support”- fill up space, structure, strength, transport, storage
- muscle tissue “movement”
- nervous tissue “control”- transmit info
primary germ layers
embryonic layers, give rise to all four tissue types in adult
ectoderm
nervous, epithelial (dermis)
mesoderm
-muscle, connective, epithelial
-endothelium(blood vessels) + mesothelium(membranes) line cavities
endoderm
epithelial (mucosa)
epithelia
covering
glands
provide fluid secretions
cellularity (feature of epithelium)
little extracellular matrix, mostly cells
contacts (feature of epithelium)
cells linked by strong junctions
polarity (feature of epithelium)
apical + basal surfaces, separate functions
attachment (feature of epithelium)
attached to C.T. via basal lamina
avascularity (feature of epithelium)
diffusion from connective tissue
regeneration (feature of epithelium)
high turnover, stem cells at basal surface
functions of epithelium tissue
- provide physical protection: abrasion, dehydration, infection
- control permeability: semi-permeable, covers all surfaces
- provide sensation: sensory neurons
- produce specialized secretions: glandular, protection, hormones
apical surface (structure of epithelium)
exposed to the environment and may have microvilli (absorption or secretion) & cilia (fluid movement)
basolateral surface (structure of epithelium)
attachment to neighboring cells via intercellular connections
basal lamina (basement membrane)
-thin layers of a specialized extracellular matrix that form the supporting structure on which epithelial & endothelial cells grow
-contain lamina lucida & lamina dense
lamina lucida
from epithelia glycoproteins + fine filaments restrict large molecule movement
lamina densa
from connective tissue coarse protein fibers provide strength
what is the classification of epithelium based on?
-shape and layers
-all shapes are hexagonal